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# Star Strider

##### Last seen: Today
13,473 2012 年以降の合計貢献数

Hic sunt dracones!

PROFESSIONAL: Physician (M.D.): Diplomate of the American Board of Internal Medicine; M.Sc. Biomedical Engineering: Instrumentation, Signal Processing, Control, System Identification, Parameter Estimation

NON-PROFESSIONAL: Amateur Extra Class Amateur Radio Operator; Private Pilot, Airplane Single Engine Land, Instrument Rating Airplane; Gamer

NOTE: I do not respond to emails or personal messages, unless they are about my File Exchange contributions.

#### Star Strider's バッジ

Finding membrane time constant from a graph
Try adding this line to your code (after the loop): tau_Vm_num = interp1(Vm_num, time, 0.632*max(Vm_num)); so the entire code...

response spectrum - time domain to frequency domain
Here is some example code that you can adapt to your data: t = linspace(0, 5, 1E+4); ...

Function handle with integrals of multiple equations?
I get different result with a strictly numeric version: V1 = 230; P1 = 2.7; T1 = 300; V2 = 30; A = -0.703029; B = 108...

Finding the index of x values to create an equally spaced array.
Your approach appears to be correct, as far as it goes. Use the interp1 function to create your result vector: x = 0:195; y ...

Chebyshev type II filter
See the documentation for: cheb2ord, cheby2, zp2sos and filtfilt.

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Suppressing only part of a function output?
To have only ‘a’ and ‘b’ returned: [a,b] = myFun(d,e) and to have only ‘c’ returned: [~,~,c] = myFun(d,e) Use variations o...

1日 前 | 0

Is there a PDF for all Matlab Functions?
There are PDF documentation for MATLAB and separately for the Toolboxes and such. For the MATLAB collection click on: PDF Docum...

1日 前 | 0

How to solve system of differential equations with time dependent parameters?
As darova suggested, integrate it numerically. For some reason, ode45 does not like the anonymous functions and throws an ’Unde...

1日 前 | 2

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Zero crossing for a curve fitting function(smoothing spline)
I don’t have the Curve Fitting Toolbox. (I only need it to reply to Answers Questions, and that’s not enough justification for ...

1日 前 | 0

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Area under FFT curve
Calculate the areas of only the ‘positive frequencies’ half of the fft output, not the entire output. If the data are all posit...

1日 前 | 0

Need to solve the roots from a large equation
Use the correct values for ‘la’ and ‘n’, then this: syms k la = 42; n = pi; Eqn = 2*k - 2*k*n + (8*k^7*n^4 - 24*k^5*n^3 + ...

2日 前 | 0

Find Middle of square wave
Use the islocalmax function (R2017b and later): This code plots green upward-pointing triangles at the centre of each pulse: ...

3日 前 | 0

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Change color of a specific line in mesh
No exact solutions without your code and data. One approach: xv = -15:0.8:15; yv = -10:0.8:10; [X,Y] = ndgrid(xv, yv); z...

3日 前 | 1

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Calculating efficiency using matlab
No loops needed: Tout = [323.2 326.0 328.8 331.6 334.3 337.1]; I = [500 550 600 650 700 750]; [Toutm,Im] = ndgrid(Tout,I...

3日 前 | 0

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Vary a parameter and plot the output
Try this: function main x0 = [500 500 500 500 5 5]; opt = optimset('Display','off'); % 'display', 'iter' I = [500 550 600 ...

4日 前 | 0

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How do I avoid using a lot of if statements in a row?
Another option is switch,case,otherwise. You will need to determine if that is an improvement over the multiple if blocks.

4日 前 | 0

Stability Analysis (Dertermining the Limit Cycle)
The phase portrait is usually plotted as the function against its derivative. Use the gradient function to calculate the deriva...

4日 前 | 0

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Peak to Peak Value of Sinusoidal Grad
Use the islocalmax function to find the maxima, islocalmin to find the minima, and go from there. (These functions were introdu...

4日 前 | 0

Solve numerically a system of first-order differential equations
Create the function symbolically: syms a b c d e f g t x(t) y(t) z(t) T Y Dx = diff(x); Dy = diff(y); Dz = diff(z); Eqn1 ...

5日 前 | 1

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Finding Angular Frequency of an Oscillation
Likely the easiest way would be to find the times of the positive peaks, then calculate from there: [pks,pktimes] = findpeaks(...

5日 前 | 1

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filter a timetable by day
I am not certain what you intend by ‘groups’. One option is to use the retime function: TTRT = retime(TT, 'daily','mean') ...

5日 前 | 0

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how do i keep the format of xticklabels?
Use compose or sprintfc to create the cell array of labels: figure plot(0:6, rand(1,7)) xtl = sprintfc('%d',10.^(0:6)); xtl...

5日 前 | 0

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creating plane piecewise in one plot
Try this: f = @(x) (3*x).*((0<x) & (x<=1)) + (2*x+1).*((1<x) & (x<=2)) + (6*x+1).*((2<x) & (x<=3)); x = linspace(0, 3); ...

5日 前 | 0

Try this (obviously with your data, not my simulated vectors): x = 1:50; ...

6日 前 | 1

"dsolve" gives some extra terms in the solution
Tell simplify to keep simplifying until it either meets the iteration limit or cannot simplify the expression further: Vs= sim...

6日 前 | 0

Nans values in time series
You must decide that. There are methods to interpolate the NaN values if you want to do that, one of which is the fillmissing...

6日 前 | 0

How can I solve an equation containing log ?
Use the fsolve function, because it will return complex results, and since the argument to the log function is negative it will ...

6日 前 | 0

How to find maximum of a function of 2 variables
One approach: z = @(x,y) cos(x.^2 + y.^2); XY = fminsearch(@(b)norm(-z(b(1),b(2))), [3; 3]) producing: XY = 2...

7日 前 | 1

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convert a transfer function to controllable and observable canonical form
num = [4]; den = [1 0.8 4]; Gp = tf (num , den); The canon function requesting the 'companion' canonical form directly produc...

7日 前 | 1

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why do I get "Undefined function or variable 'tspan'."
The code defines that variable as ‘timespan’. The argument names and the varialble names must always match. Try this: [t,z...

7日 前 | 1

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